Common pitfalls

Initialization of intervals

The statement x = 0.1 in Python means to assign to x a floating-point number that approximates 1/10 (see Python’s tutorial). This poses a problem when initializing an interval:

from verry import FloatInterval as FI
x = FI(0.1)  # This is wrong.
x = FI("0.1")  # The correct initialization is this.

It is recommended to specify endpoints by strings or integers whenever possible.

Limitations with constants and conditional branches

Currently, several features in Verry do not support a function that is a constant or contains conditional branches. This limitation comes primarily from the automatic differentiation (AD). Verified computation often requires the value of derivatives to measure approximation errors, and derivatives are computed using AD. However, it is difficult to make AD work with aforementioned functions.